In vehicles, a torque limiter device that interrupts a torque of a predetermined value or greater may be arranged between an engine and a transmission in view of breakage of the transmission and the like due to an excessive torque transmitted from the engine. This torque limiter device is configured, e.g., such that one or more friction facings are held between a pair of plates with a predetermined holding force, and input and output sides of the device are coupled to a flywheel, i.e., a member on the engine side, and an input shaft or the like on a transmission side, respectively.
This kind of torque limiter device has a drive plate that is provided at its radially outer portion with a frictional coupling portion held between a pair of plates with a predetermined holding force, a driven-side member coupled to an input shaft of a transmission, and a spring damper arranged between them (see, e.g., patent reference 1). In this device, the paired plates holding the frictional coupling portion therebetween (or a damper cover arranged on a radially outer portion of the frictional coupling portion) is coupled to a flywheel. Conical springs bias one of the plates toward the frictional coupling portion to apply the holding force to the frictional coupling portion.
In this torque limiter device, the torque of the engine is transmitted from the flywheel via the frictional coupling portion to the drive plate, and is further transmitted therefrom via the spring damper to the driven-side member and the input shaft of the transmission. When the torque provided from the engine exceeds a predetermined torque, sliding occurs between the frictional coupling portion and the plates. Thereby, a torque exceeding the predetermined torque is not transmitted toward the transmission, and breakage of the transmission due to transmission of the excessive torque can be prevented.
[Patent Reference 1] Japanese Laid-Open Patent Publication No. 2002-39210